One endpoint for preview URL writes, selected by op:

• create (name, url, optional isDefault): returns 201 { object: "preview_url", previewUrl }. 409 when the project already has a preview with this URL. Setting isDefault: true unsets the previous default.
• update (id, optional name, url, isDefault): returns 200 { object: "preview_url", previewUrl }. 409 when another preview of this project already has the new URL.
• delete (id): returns 200 { object: "preview_url_deleted", id }. Permanent.

name is at most 191 characters and url at most 2048. Ids are resolved through this project; an id from another project returns 404.

Required scope: project:manage